Nice! I think you can approximate timing somewhat, by making your web server create the "jpeg" on the fly and send it to the client in timed chunks. The source could even be a webcam, so the "jpeg" would go on forever.

There are already webcams which do this- but they use a mime trick for 'multipart/x-mixed-replace'.

That's basically the server telling the client 'That data I just sent you, well now replace it with this new thing'.

No JavaScript needed, and can work with plain http and jpeg